Cool Equipment: Magnetic Mixer and Solutions
FRAMEWORK
I.
Scientific and Engineering Practices
II.
Cross-Cutting Concepts
III.
Physical Sciences
SKILLS/OBJECTIVES o Learn the difference between a mixture and solution, solute vs. solvent, and properties of dissolving and separating solutions and mixtures o Learn how to use a magnetic mixer!
MATERIALS
Plastic cups
Coffee Filters
Water
Oil
Flour
Sugar
Sand
Blue Food Coloring
Kool aid
Magnetic mixer
Beaker
Scoopula
Some Examples of Mixtures:
Chex mix
-Salad
-Gravel
Some Examples of Solutions:
-Lemonade
-Apple Juice
-Plastic
-Cement-Chip
-Brass
-Steel o

NOTES
Do not let the kids eat the food!
Activity # 1 Mixture v. Solution
Materials Chex mix
Salad
Lemonade
Apple Juice
Plastic
Cement-Chip
Brass
Steel plastic cups
Worksheet Y/N
· In this lesson we will learn to tell the difference between solutions and mixtures!
Have a small sample of each of these items in a cup. Ask the kids to vote on whether they think each sample is a mixture or a solution.
How can we tell?
Well a solution is homogenous , the same throughout. Visibly we can see Chex Mix, and salad is a mixture, you can see little individual pieces. Pick out all of the different components
Now look at the lemonade and apple juice. These are solutions!
When you look at them you cannot see any particles or pick them out!
They are homogenous
Now look at the solids: cement, brass, and steel. Not all mixtures are liquids! See the chunks of rock in the cement. You could chip them away and separate the mixture into its components! Now look at the steel and brass. These are called alloys , blends of metal, that are solutions. You can’t see the different components!
What do you think it takes to make a mixture? How about a solution?
Let’s find out!

.
Activity # 2 Separating Solution
Materials -Coffee Filters
-Cups
-Water
-Oil
-Flour
-Sugar
-Sand
-Blue Food Coloring
-Kool aid
-Magnetic mixer
Worksheet N
· How do we make a solution!
In the lab we have this piece of equipment called a Magnetic stirrer! It helps dissolve solutions for experiments!
How it works: there is a magnetic bar inside with different poles, north and south! The machine creates a rotating magnetic field that causes the poles to alternately be attracted to a singular point, making the magnet spin, and make a vortex!
Let’s try to make solutions! Add water to the beaker and drop in the magnet. Next add two teaspoons of the solute, and turn on the mixer! Explain to the kids that the solute is dissolving, or breaking up into the mixture aka the sugar is the solute and water the solvent
Now we have to test if it is a true solution! Have the kids vote on each. P ut a coffee filter over a beaker and pour the “solutions” over it. If it is a true solution than nothing should be left in the coffee filter.
Activity # 3 Saturation
Materials -Salt
-Water
-Beaker
-Scoopula
Worksheet N

Only a certain amount of solute can be dissolved into a solvent!
Just like there are only a certain number of seats on a bus, there is a set amount of room to dissolve particles into the solvent before it becomes oversaturated!
Once a certain amount of salt is dissolved into a container of water, the solution is saturated and no more salt will be able to dissolve. Each student will have a beaker of water that they will add salt to until the solution is saturated.
They will first fill containers with water.
They then will use the scoopula to slowly add bits of salt- checking each time if it all dissolved into the water. The students will keep adding salt until solid undissolved salt particles are visible in the water.
Have the kids raise their hands if they see the visible salt. See if anyone can anyone can identify the solution as a saturated solution and explain why. If no students are able to do this, explain it to them.
Activity # 4 Separating Mixtures
Materials -Sugar
-Sand
-Water
-Coffee Filters
-Cups
Worksheet N
How can we use the different properties of mixtures and solutions in real life?
How would you separate a mixture of salt and sand?
Have the kids examine a cup containing a mixture of sugar and sand and have them attempt to separate the two substances by hand o o
How long would this take? Is there an easier way?
How can we apply what we have learned about solutions and mixtures to solve this problem?
Form a hypothesis!

o Sand and water together form a mixture that can be separated by the coffee filter, while sugar and water form a solution that cannot be separated by the filter.
Add enough water to the cup to dissolve all of the sugar. Use the magnetic stirrer to speed the process. Let the water settle.
The sugar should be gone, while the sand stays at the bottom.
Strain through a coffee filter into a new container-- the sand should stay in the coffee filter, while the water and dissolved sugar solution should pass through.
o We have now separated the sugar and the sand!
o Explain to the kids that we were able to do this because salt and water form a solution , while sand and water form a mixture .